Data Analysis Expressions and MDX

SQL Server 2008 R2

The Data Analysis Expressions (DAX) language is a new formula language that you can use in PowerPivot workbooks. DAX is not a subset of MDX, but a new formula language that is considered an extension of the formula language in Excel. The DAX statements operate against an in-memory relational data store, comprised of tables and relationships in the PowerPivot workbook. You use DAX to create custom measures and calculated columns.

This section explains how DAX is embedded in XMLA messages, and provides links to technical reference topics for the DAX functions and operators.

Note

DAX expressions cannot be used where an MDX expression is required and vice versa.

DAX formulas can only be used in Excel workbooks that contain PowerPivot data. You create DAX formulas within a PowerPivot workbook by typing a formula in a calculated column or in a measure.

You can view the DAX expressions that are sent to the in-memory storage engine if you monitor the interactions between the PowerPivot client and the local Analysis Services instance. To do this, you can create a trace on the workbook and view the trace by using SQL Server Profiler. For information about how to create a trace on a PowerPivot workbook, see the PowerPivot for Excel help documentation.